1. Technical Field
The present invention relates to a method of and apparatus for producing scrap-free gaps in flat back plastic filament coil slide fastener chain without damaging the tapes of the chain.
2. Description of the Prior Art
Numerous apparatuses and methods of gapping slide fastener chain are present in the patented prior art. One example of the prior art is present in U.S. Pat. No. 3,490,133. That patent discloses a punch and die apparatus for acting on interlocked filament coil slide fastener chain to gap the chain at regular intervals by first severing outer leg portions of the coil elements and subsequently gripping and punching out the remaining interlocked interior portions of the coil elements.
The referenced patented gapping arrangement includes no provision for laterally engaging and stabilizing the central interior portions of the coil elements as they are punched, and consequently there is a possibility that, at the time of punching, the central interior coil portions may be displaced laterally due to lack of control with the result that some plastic filament scrap may remain attached to the tapes at the completion of the gapping operation. Moreover, in the patented arrangement, there is no definite provision for conveying away the severed exterior leg portions of the coil elements or the interior portions thereof, and to this extent the patented method is somewhat haphazard.